I am a graduate student in a group that has a Lake Shore 335 Temperature Controller as part of a set up for doing Mossbauer experiments at cryogenic temperatures (2-200 K).
Recently we have developed a new issue which is that when the heater range is set to high the temperature will be stable but not accurate to the set temperature. Typically the achieved temperature is 0.3 to 0.6 K higher than the set temperature. The heater will be on at approximately 20-25% at the time which in the past has provided more than enough dynamic range to achieve the desired temperature. See attached image below for an example.
Using the system on the other heater ranges (i.e. low or medium) provides both stable and accurate temperatures.
We did recently have an issue that required soldering some of the wires that run from the silicon diode to the temperature sensor B (otherwise it was not registering a temperature) but it's not clear to me what, if any possible relationship there is between these issues.
Thank you very much in advance for your time and consideration.
Post by Lake Shore Ogi on Jul 31, 2018 8:15:08 GMT -5
The most likely reason is that you have a value set for your manual output. The manual output essentially acts like an offset - so whatever the PID algorithm wants to drive, the manual output will add to that. Please press the manual output button and check if there is a value other than zero. If there is, set it to zero and press the enter key to confirm.